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Boot
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Cruising Guide for the Florida Keys & Cuba |
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ELECTRONIC STORM TRACKING - HURRICANE CHARLEY P/C Gregory Absten, August 2004 Hurricane Charley just wreaked its devastation on SW Florida, narrowly missing us here in the Florida Keys. As storms pop up there is some very specific information and graphics available through NOAA that go far beyond the simple displays you’ll see on the Weather Channel, though those are very helpful. Here we’ll look at several good examples, but a lot more is waiting for you to explore on the NOAA website. All the websites listed here start with http://. Go to www.nhc.noaa.gov for the National Hurricane Center’s Tropical Weather home page. As you get to that page you’ll see that any named storm or Tropical Depression (TD) is listed at the top for both the Atlantic and Pacific. If none has yet formed just go down a bit and look for the “Tropical Outlook” to get an idea of whether the environment might be ripe to spawn some event in the coming days. On the same home page you’ll also find a “Tropical Discussion” that will explain the vagaries in a bit more depth. If a TD or storm is named at the top then there will be associated links for “Public Advisories”, “Discussion” and “Maps and Charts” which I find useful. The Advisory is the public statement and warnings. The discussion goes into more depth and importantly lets you know how certain or uncertain the forecasters are of the storms track. Maps and Charts display information graphically so you can start planning your own strategy. On this Maps and Charts page you can find the graphic for the 3-5 day forecast track as shown below.
This is the 5 day forecast track for Charley as of August 11th, two days before landfall. The three day segment is shown in white and the last two days with just an outline and track. What you’ve read under the “discussion” will tell you how certain or uncertain the forecaster might be of the path. As the storm gets closer to land the “Strike
probabilities” section will give you more detail on the projected path along
with anticipated variances. The chart below shows the probabilities of the
Hurricane “striking” within a 3 day period. This chart is at 2 am August 13th, the day that Charley struck the Punta Gorda area. Red shows where the storm is, orange indicates a 50-99% chance of being there within 72 hours, green a 20-49% for the same time, and yellow a 10-19% chance. This chart clearly shows that the Punta Gorda area was in a high probability “hit” area. I’ve heard many criticisms of the official forecasting because people thought it was going to Tampa and not where it did. The Forecast Track shown above does indicate a path toward Tampa, but an informed viewer would be looking at this Strike Probability Chart to determine a more realistic assessment of a possible hit and it very clearly is there. It was similarly there on the August 11th Chart, although in green because of the 2 day time factor. On August 12th the Discussion page stated that “… While the spread in the NHC model guidance has increased somewhat for this advisory package …”, which indicates that there was increasing uncertainty in the storm staying on-center on the actual forecast track. The Satellite imagery is not as useful for planning purposes as the charts above but is very interesting to view, particularly in the motion views. Clicking on the satellite imagery link on the left side of the main NOAA page gives you many choices on Satellite views. Look at the GOES-East/West Hurricane Sectors, under ATLANTIC, then look at the IR image (infra-red, but you can also see the visible or water vapor images). If you have a high speed connection then click on the “View Movie” under the image – this shows a moving satellite image and you can literally watch the tops of the thunderstorms exploding into action in this view. This is a small excerpt of the IR (infrared) Satellite image which ordinarily shows all of the Gulf and out into the Atlantic almost to Africa. This is about 4am in the morning the day Charley hit. One of the perspectives this gives is that the simple track marks you see on TV do not really portray the size and scope of the storm. Here in Marathon Florida we were fortunate to have only about 50 mph winds as the storm passed.
The IR color Satellite photo at right shows Charley later that day as it made landfall. These photos are on a different page than the one shown above – just keep exploring the links to find these. Sometimes they’re under the “Storm Tracker” Satellite. The weather channel also has nice color satellite photos at www.weather.com when a hurricane has been named. (choose tropical storm update from front page, then tropical Atlantic satellite from the pull down window, then click to enlarge) The “Cumulative Wind Distribution” is historical and shows the “wind path” the storm has left. This one is on August 15th – two days after Charley made landfall. Red shows hurricane force and orange tropical storm force winds. Wind speed forecast and probability gives you an
indication of how strong the forecasters think the winds might be to about 3
days out, and compares the levels to the Categories of hurricanes.
Even though Charley was a Category III when it made landfall, this graph two days previously shows that the highest probability was still Category I, but acknowledged that it had about a 10% chance of becoming Category III -- which it did. www.srh.noaa.gov/radar/latest/DS.p19r0/si.kbyx.shtml will take you to “almost live” radar for the Florida Keys and gives you the additional option of watching it as a movie over the last several hours (I click on the “Composite Reflectivity – Long Range – Loop”). From that South Florida radar page you can hit links to look at the entire U.S. or choose radar state by state. Here’s one from the middle of the state showing the bands of thunderstorms from Charley after it made landfall. A last piece of information, in case you decide to run in
advance of a storm up the coast somewhere to find better protection, is to view
the waves forecast graphics. This one shows the waves out As a boater, deciding what to do about impending storms and preparing your boat is another story. For an indepth discussion of boating strategies here in the Florida Keys go to www.BootKeyHarbor.com/hurricanes.htm . I’ve made it easier to go to many of these weather sites
by locating the shortcut links to them on the home page of
www.BootKeyHarbor.com . Look at
the bottom left of the front page for the links to the Hurricane Center, Keys
marine weather, radar, tides, waves and more. |
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Boot Key Harbor website created and maintained by Capt. Gregory
T. Absten, Marathon. - A Boater's Guide to the Florida Keys & Cuba |
Radar
images become useful as these storms move onshore. You can see the individual
bands and storm cells that might affect your location. This is also extremely
useful just to watch for normal local afternoon thunderstorms or fronts moving
through. 
from Charley the day it made landfall. Red areas are seas over 14 ft, and even
the light green are 6-8 ft. These graphics show the forecast for several days
in advance. You wouldn’t wait until the last minute to move or to use these, but
if you view them several days in advance of an approaching storm (or just a
routine crossing to the Bahamas or Cuba), you get a better idea of forecast
seas. You can find these at